Poisonous Rocks: Identifying Toxic Minerals
Asbestos
Mg3Si2O5(OH)4
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Danger Type:
- Particulate/ Inhalation
Encounter
Asbestos will be encountered at asbestos mines for commercial use, and may also be found in small amounts at serpentine quarries.
Bumble Bee Jasper
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Danger Type:
- Particulate/ Inhalation
- Ingestion
Encounter
Bumble Bee Jasper is encountered almost exclusively as lapidary material sourced from volcanic deposits in Indonesia. It appears as banded yellow, orange, black, and gray material and is commonly sold in rock shops as polished slabs, cabochons, and carvings. It is rarely encountered in the field outside of its source region.
Chrysotile
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Danger Type:
- Particulate/ Inhalation
Encounter
Chrysotile is encountered at asbestos mines and in serpentinized ultramafic rock formations. It may appear as silky white, greenish, or gray fibrous veins running through host rock. Chrysotile can also be encountered in older construction materials and industrial products due to its historical use. In natural settings, it is most dangerous when weathered or exposed, allowing fibers to become airborne.
Cinnabar
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Danger Type:
- Particulate/ Inhalation
- Ingestion
Encounter
Cinnabar is encountered in hydrothermal veins and near volcanic or geothermal activity. It appears as bright red crystalline masses or granular coatings and is often associated with quartz, calcite, and hot-spring deposits. It is commonly found in mineral collections and rock shops due to its vivid color and historical significance as the main source of mercury.
Cobaltite
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Danger Type:
- Particulate/ Inhalation
- Ingestion
Encounter
Cobaltite is encountered in hydrothermal veins and contact metamorphic deposits, often associated with nickel, silver, and other cobalt minerals. It typically appears as metallic gray to silver crystals or massive aggregates. It is most commonly seen in mineral collections and rock shops, and is rarely worked as lapidary material due to its toxicity and brittleness.
Covellite
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Danger Type:
- Particulate/ Inhalation
- Ingestion
Encounter
Covellite is encountered in copper-rich environments, commonly forming as a secondary mineral in the oxidation zones of copper deposits. It appears as deep indigo-blue to purple metallic coatings, plates, or massive material, often associated with minerals such as chalcocite, bornite, and chalcopyrite. It is commonly seen in mineral collections and rock shops due to its distinctive color, but is rarely used as lapidary material.
Galena
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Danger Type:
- Particulate/ Inhalation
- Ingestion
- Handling
Encounter
Galena will be encountered in galena mines, often as cubes. The dirt around them commonly has sulfur and can be smelt when digging, as well as being visibly yellow. Galena is a staple of almost every rock shop as it is affordable, common and incredibly shiny.
Orpiment
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Danger Type:
- Particulate/ Inhalation
- Ingestion
Encounter
Orpiment is encountered in hydrothermal deposits, often alongside realgar and other arsenic-bearing minerals. It typically appears as bright yellow crystalline masses, foliated aggregates, or powdery coatings. It is most commonly seen in mineral collections, museums, and older pigment or mineral reference materials due to its historical use as a yellow pigment.
Realgar
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Danger Type:
- Particulate/ Inhalation
- Ingestion
- Light Degradation
Encounter
Realgar is encountered in hydrothermal deposits, commonly alongside orpiment and cinnabar. It appears as bright red to orange crystalline masses or granular coatings. It is most often seen in mineral collections, museums, and older educational or lapidary material due to its vivid color, despite being unsuitable for handling or working.
Silver Ore
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Danger Type:
- Particulate/ Inhalation
- Ingestion
Encounter
Silver ore is encountered in hydrothermal veins and polymetallic deposits, often alongside galena, sphalerite, chalcopyrite, and arsenic-bearing minerals. It may appear as dull gray to black massive material, metallic grains, or sulfide-rich rock. It is commonly seen in mineral collections and rock shops, particularly from historic mining districts.
